1. Field of the Invention
The disclosures herein relate to a touch panel.
2. Description of the Related Art
A touch panel (i.e., touchscreen panel) is an input device that allows input to be directly entered into a display, and is generally placed in front of the display. Touch panels are widely used in various applications because of their capability of allowing direct inputting based on visual information provided by the display.
A resistive-type touch panel and a capacitive-type touch panel are widely known in the art. The resistive-type touch panel includes an upper electrode substrate and a lower electrode substrate having respective transparent conductive films. These substrates are arranged such that the corresponding transparent conductive films face each other. When pressure is applied to a point on the upper electrode substrate, the transparent conductive films are brought into contact with each other, thereby allowing the position of the pressed point to be detected.
The capacitive-type touch panel detects an electrical current as the current flows through a transparent electrode or the like in response to a finger or the like coming into the close proximity of the touch panel, thereby detecting the relevant position.
The capacitive-type touch panel employs a capacitive-coupling-based detection mechanism, and, thus, can detect the position of a point that is touched, even in the absence of pressure being applied. Contact by an insulating object, however, cannot cause its contact position to be detected. The resistive-type touch panel does not require an object coming into contact with the touch panel to be made of any particular type of material. However, certain pressure needs to be applied to the touch panel because position detection is performed based on a physical contact between a transparent conductive film serving as an upper resistive film and a transparent conductive film serving as a lower resistive film.
Failure to detect the position of a contact made by an insulating object limits the places and applications in which the touch panel is used. The area of use thus ends up being limited.
Accordingly, it may be desirable to provide a touch panel that can be operated by an insulating object coming in contact with the touch panel, even in the absence of applied pressure.    [Patent Document 1] Japanese Patent Application Publication No. 2000-76014    [Patent Document 2] Japanese Patent Application Publication No. 2006-268262    [Patent Document 3] Japanese Patent Application Publication No. 2010-157029    [Patent Document 4] Japanese Patent Application Publication No. 2011-221676